After I sleep down my notebook (Xubuntu 12.04) and wake up, my network setting goes often corrupted and does not work. Only solution seems to be restart.

Connecting and disconnecting in network manager or sudo ifconfig eth0 down and later up does not help.

Sometimes the RJ45 connector is blinking, sometimes not even that. Occasionally other network cards (Wifi) gets jammed similarly, but I do not use them so often and I do not know if this is the same problem.

I'm running a virtualbox Windows 7 bridged to both network interfaces, do not know if there is some glue to that problem.

Is there a way how to completely init the network module in case this happen?

Edit: Using the responses bellow I have discovered, that nothing from sudo service networking restart or /etc/init.d/networking restart helped to bring the network card alive, once it gets "dead". Sometimes, the card is not even blinking like it would be disabled. Sometimes card is blinking, but no response, no IP address is assigned. Only solution is to switch notebook off and on again. Could it be a hardware problem? I have little comparison with dual-booted Windows, but it happens so rarely, that I had no opportunity to observe it on different OS.